Saturated and unsaturated fatty acids differentially regulate in vitro and ex vivo placental antioxidant capacity

Zuogui Pills alleviate cyclophosphamide-induced ovarian aging by reducing oxidative stress and restoring the stemness of oogonial stem cells through the Nrf2/HO-1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Zuogui Pill (ZGP) is a traditional herbal formula of Chinese Medicine with a long history of use in alleviating ovarian aging.

AIM OF THE STUDY

To examine the impact of ZGP on oxidative stress and the stemness of oogonial stem cells (OSCs) in cyclophosphamide (CTX)-induced ovarian aging, as well as its molecular mechanisms involving the nuclear factor erythroid 2-related factor 2 (Nrf2, NFE2L2)/heme oxygenase-1 (HO-1, Hmox1) pathway.

MATERIALS AND METHODS

Female Sprague-Dawley (SD) rats were randomly divided into seven groups: control, model (CTX), estradiol valerate (EV, 0.103 mg/kg), ZGP-L (low dose Zuogui Pill, 1.851 g/kg), ZGP-H (high dose Zuogui Pill, 3.702 g/kg), ML385 (30 mg/kg), and ML385+ZGP-L. After CTX modeling, the EV, ZGP-L, ZGP-H, and ML385+ZGP-L groups were treated by gavage for 8 weeks, while the ML385 and ML385+ZGP-L groups were administered the Nrf2 antagonist ML385 twice a week. OSCs were isolated after modeling and then treated with drug serum containing 10% ZGP or 10 μM ML385. The general conditions of the rats, including body weight, ovarian weight/body weight ratio, and estrous cycle, were observed. Ovarian ultrastructure, follicle and corpus luteum counts were assessed via hematoxylin and eosin (H&E) staining. Serum hormone levels were measured using enzyme-linked immunosorbent assay (ELISA). Nrf2/HO-1 pathway, stem cell, germ cell, and cell cycle biomarkers were analyzed by qPCR and Western blot. Cell viability was assessed by cell counting kit-8 (CCK-8) assay. Oxidative stress biomarkers were evaluated using flow cytometry and assay kits. Immunofluorescence was employed to detect and locate OSCs in the ovary, quantify the average fluorescence intensity, and identify OSCs.

RESULTS

After ZGP treatment, rats with CTX-induced ovarian aging exhibited improved general condition, increased body weight, higher total ovarian weight to body weight ratio, and a restoration of the estrous cycle similar to the control group. Serum levels of estradiol (E2) and follicle stimulating hormone (FSH), two sex hormones, were also improved. Ovarian ultrastructure and follicle count at all stages showed improvement. Moreover, the viability and proliferation capacity of OSCs were enhanced following ZGP intervention. The Nrf2/HO-1 pathway was found to be down-regulated in CTX-induced aging ovarian OSCs. However, ZGP reversed this effect by activating the expression of Nrf2, HO-1, and NAD(P)H oxidoreductase 1 (NQO1), increasing the activity of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), and reducing the accumulation of malonaldehyde (MDA) and reactive oxygen species (ROS), thus restoring resistance to oxidative stress. Additionally, ZGP improved the cell cycle of OSCs, up-regulated the expression of Cyclin D1 and Cyclin E1, restored cell stemness, promoted proliferation, enhanced the expression of cell stemness markers octamer-binding transcription factor 4 (Oct4) and mouse VASA homolog (MVH), and down-regulated the expression of P21, thereby inhibiting apoptosis. The therapeutic effects of ZGP against oxidative stress and restoration of cell stemness were attenuated following inhibition of the Nrf2 signaling pathway using ML385.

CONCLUSIONS

ZGP protected against CTX-induced ovarian aging by restoring normal ovarian function, alleviating oxidative stress in aging OSCs, promoting OSCs proliferation, and restoring their stemness in rats, possibly through regulating the Nrf2/HO-1 pathway.

Linoleic Acid Alleviates Lipopolysaccharide Induced Acute Liver Injury via Activation of Nrf2

Linoleic acid (LA) not only functions as an essential nutrient, but also profoundly modulates oxidative stress and inflammatory response. However, the potential mechanisms have not been adequately researched. Hence, this study examined the potential pharmacological roles of LA and the underlying mechanisms in mice with lipopolysaccharide (LPS)-associated acute liver injury (ALI). The results indicated that treatment with LA alleviated the histopathological abnormalities in the hepatic and plasma levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutathione-S-transferase (GST) in mice with LPS exposure. In addition, LA inhibited the LPS-associated generation of proinflammatory factors, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), and downregulated the hepatic myeloperoxidase (MPO) level. In addition, the administration of LA resulted in a reduction in hepatic malondialdehyde (MDA) levels and an elevation in liver superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), and glutathione peroxidase (GSH-PX) levels. Further investigations revealed that LA promoted the expression of nuclear factor E2-related factor (Nrf2) and NAD(P)H: quinone oxidoreductase 1 (NQO1). In addition, the beneficial outcomes of LA on LPS-induced acute liver failure were revered when Nrf2 was pharmacologically suppressed by ML385. These experimental results demonstrated that LA supplementation attenuated LPS-associated acute hepatic impairment in mice via the activation of Nrf2.

A Proteomic Study of the Effect of N-acetylcysteine on the Regulation of Early Pregnancy in Goats

Simple Summary

Early pregnancy regulation is an extremely complex process that is influenced by various factors. We previously mined the differentially expressed genes affected by N-acetyl-L-cysteine (NAC) in early pregnancy in goats via transcriptome sequencing. We found that NAC increased the number of lambs by affecting the immune pathway in ewes and enhancing antioxidation. Based on this, we here explored the effect of NAC on early pregnancy in goats at the protein level. The results showed a difference in the expression of uterine keratin and increases in the levels of antioxidant indices and hormones in doe serum.

Abstract

Dietary supplementation with N-acetyl-L-cysteine (NAC) may support early pregnancy regulation and fertility in female animals. The purpose of this study was to investigate the effect of supplementation with 0.07% NAC on the expression of the uterine keratin gene and protein in Qianbei-pockmarked goats during early pregnancy using tandem mass spectrometry (TMT) relative quantitative proteomics. The results showed that there were significant differences in uterine keratin expression between the experimental group (NAC group) and the control group on day 35 of gestation. A total of 6271 proteins were identified, 6258 of which were quantified by mass spectrometry. There were 125 differentially expressed proteins (DEPs), including 47 upregulated and 78 downregulated proteins, in the NAC group. Bioinformatic analysis showed that these DEPs were mainly involved in the transport and biosynthesis of organic matter and were related to the binding of transition metal ions, DNA and proteins and the catalytic activity of enzymes. They were enriched in the Jak-STAT signalling pathway, RNA monitoring pathway, amino acid biosynthesis, steroid biosynthesis and other pathways that may affect the early pregnancy status of does through different pathways and thus influence early embryonic development. Immunohistochemistry, real-time quantitative PCR and Western blotting were used to verify the expression and localization of glial fibrillary acidic protein (GFAP) and pelota mRNA surveillance and ribosomal rescue factor (PELO) in uterine horn tissue. The results showed that both PELO and GFAP were localized to endometrial and stromal cells, consistent with the mass spectrometry data at the transcriptional and translational levels. Moreover, NAC supplementation increased the levels of the reproductive hormones follicle-stimulating hormone (FSH), luteinizing hormone (LH), oestradiol (E2), progesterone (P4), superoxide dismutase (SOD), glutamate peroxidase (GSH-Px) and nitric oxide (NO) in the serum of does. These findings provide new insight into the mechanism by which NAC regulates early pregnancy and embryonic development in goats.

Palmitic Acid Impedes Extravillous Trophoblast Activity by Increasing MRP1 Expression and Function

Normal function of placental extravillous trophoblasts (EVTs), which are responsible for uteroplacental vascular remodeling, is critical for adequate delivery of oxygen and nutrients to the developing fetus and normal fetal programming. Proliferation and invasion of spiral arteries by EVTs depends upon adequate levels of folate. Multidrug resistance-associated protein 1 (MRP1), which is an efflux transporter, is known to remove folate from these cells. We hypothesized that palmitic acid increases MRP1-mediated folate removal from EVTs, thereby interfering with EVTs' role in early placental vascular remodeling. HTR-8/SVneo and Swan-71 cells, first trimester human EVTs, were grown in the absence or presence of 0.5 mM and 0.7 mM palmitic acid, respectively, for 72 h. Palmitic acid increased ABCC1 gene expression and MRP1 protein expression in both cell lines. The rate of folate efflux from the cells into the media increased with a decrease in migration and invasion functions in the cultured cells. Treatment with N-acetylcysteine (NAC) prevented the palmitic acid-mediated upregulation of MRP1 and restored invasion and migration in the EVTs. Finally, in an ABCC1 knockout subline of Swan-71 cells, there was a significant increase in invasion and migration functions. The novel finding in this study that palmitic acid increases MRP1-mediated folate efflux provides a missing link that helps to explain how maternal consumption of saturated fatty acids compromises the in utero environment.

The role of nuclear factor erythroid 2-related factor 2 (NRF2) in normal and pathological pregnancy: A systematic review

OBJECTIVE

A homeostatic balance between reactive oxygen species production and the antioxidant redox system is an important component of normal pregnancy. Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) preserves cellular homeostasis by enhancing the cell's innate antioxidant status to reduce oxidative stress and inflammatory damage to the cell during pregnancy. Active Nrf2, in the nucleus of the cell, transactivates various antioxidant genes. The objective of this systematic review was to synthesize evidence on the role of Nrf2 in various adverse pregnancy outcomes (APOs).

METHODS

We conducted a systematic review of the role of Nrf2 in pregnancy. Articles written in English, Portuguese, and Spanish were obtained from three different databases from inception until January 2021. The titles, abstracts and full text were reviewed independently by six reviewers. The quality of the included studies was assessed using a quality assessment tool developed to assess basic science and clinical studies. Nrf2 expression (gene and protein), functional contributions, and association with APOs were assessed.

RESULTS

A total of 747 citations were identified; 80 were retained for full review. Most studies on Nrf2 have been carried out using placental tissues and placenta-derived cells. Limited studies have been conducted using fetal membranes, uterus, and cervix. Nuclear translocation of Nrf2 results in transactivation of antioxidant enzymes, including glutathione peroxidase, hemeoxygenase-1, and superoxide dismutase in gestational cells during pregnancy. This antioxidant response maintains cellular homeostasis during pregnancy. This promotes trophoblast cell survival and prevents cell death and abnormal angiogenesis in the placenta. Excessive and insufficient Nrf2 response may promote oxidative and reductive stress, respectively. This Nrf2 dysregulation has been associated with APOs including gestational diabetes mellitus, intrauterine growth restriction, reproductive toxicity, preeclampsia, and preterm birth.

CONCLUSION

Several studies have localized and reported an association between Nrf2's differential expression in reproductive tissues and the pathogenesis of APOs. However, a comprehensive functional understanding of Nrf2 in reproductive tissues is still lacking. Nrf2's activation and functions are complex, and therefore, current in vitro and in vivo studies are limited in their experimental approaches. We have identified key areas for future Nrf2 research that is needed to fill knowledge gaps.

Effects of Maternal Obesity On Placental Phenotype

The incidence of obesity is rising rapidly worldwide with the consequence that more women are entering pregnancy overweight or obese. This leads to an increased incidence of clinical complications during pregnancy and of poor obstetric outcomes. The offspring of obese pregnancies are often macrosomic at birth although there is also a subset of the progeny that are growth-restricted at term. Maternal obesity during pregnancy is also associated with cardiovascular, metabolic and endocrine dysfunction in the offspring later in life. As the interface between the mother and fetus, the placenta has a central role in programming intrauterine development and is known to adapt its phenotype in response to environmental conditions such as maternal undernutrition and hypoxia. However, less is known about placental function in the abnormal metabolic and endocrine environment associated with maternal obesity during pregnancy. This review discusses the placental consequences of maternal obesity induced either naturally or experimentally by increasing maternal nutritional intake and/or changing the dietary composition. It takes a comparative, multi-species approach and focusses on placental size, morphology, nutrient transport, metabolism and endocrine function during the later stages of obese pregnancy. It also examines the interventions that have been made during pregnancy in an attempt to alleviate the more adverse impacts of maternal obesity on placental phenotype. The review highlights the potential role of adaptations in placental phenotype as a contributory factor to the pregnancy complications and changes in fetal growth and development that are associated with maternal obesity.

Maternal high fat diet-induced obesity affects trophoblast differentiation and placental function in mice†

Evidence suggests that maternal obesity (MO) can aggravate placental function causing severe pathologies during the perinatal window. However, molecular changes and mechanisms of placental dysfunction remain largely unknown. This work aimed to decipher structural and molecular alterations of the placental transfer zone associated with MO. To this end, mice were fed a high fat diet (HFD) to induce obesity before mating, and pregnant dams were sacrificed at E15.5 to receive placentas for molecular, histological, and ultrastructural analysis and to assess unidirectional materno-fetal transfer capacity. Laser-capture microdissection was used to collect specifically placental cells of the labyrinth zone for proteomics profiling. Using BeWo cells, fatty acid-mediated mechanisms of adherens junction stability, cell layer permeability, and lipid accumulation were deciphered. Proteomics profiling revealed downregulation of cell adhesion markers in the labyrinth zone of obese dams, and disturbed syncytial fusion and detachment of the basement membrane (BM) within this zone was observed, next to an increase in materno-fetal transfer in vivo across the placenta. We found that fetuses of obese dams develop a growth restriction and in those placentas, labyrinth zone volume-fraction was significantly reduced. Linoleic acid was shown to mediate beta-catenin level and increase cell layer permeability in vitro. Thus, MO causes fetal growth restriction, molecular and structural changes in the transfer zone leading to impaired trophoblast differentiation, BM disruption, and placental dysfunction despite increased materno-fetal transfer capacity. These adverse effects are probably mediated by fatty acids found in HFD demonstrating the need for obesity treatment to mitigate placental dysfunction and prevent offspring pathologies.

Palmitic acid activates NLRP3 inflammasome and induces placental inflammation during pregnancy in mice

Maternal obesity is one of the major risk factors for pregnancy complications and is associated with low-grade chronic systemic inflammation due to higher levels of pro-inflammatory cytokines such as interleukin (IL)-1β. Pregnant women with obesity have abnormal lipid profiles, characterized by higher levels of free fatty acids, especially palmitic acid (PA). Previously, we reported that PA stimulated IL-1β secretion via activation of NLRP3 inflammasome in human placental cells. These observations led us to hypothesize that higher levels of PA induce NLRP3 inflammasome activation and placental inflammation, resulting in pregnancy complications. However, the effects of PA on NLRP3 inflammasome during pregnancy in vivo remain unclear. Therefore, PA solutions were administered intravenously into pregnant mice on day 12 of gestation. Maternal body weight was significantly decreased and absorption rates were significantly higher in PA-injected mice. The administration of PA significantly increased IL-1β protein and the mRNA expression of NLRP3 inflammasome components (NLRP3, ASC, and caspase-1) within the placenta. In murine placental cell culture, PA significantly stimulated IL-1β secretion, and this secretion was suppressed by a specific NLRP3 inhibitor (MCC950). Simultaneously, the number of macrophages/monocytes and neutrophils, together with the mRNA expression of these chemokines increased significantly in the placentas of PA-treated mice. Treatment with PA induced ASC assembling and IL-1β secretion in macrophages, and this PA-induced IL-1β secretion was significantly suppressed in NLRP3-knockdown macrophages. These results indicate that transient higher levels of PA exposure in pregnant mice activates NLRP3 inflammasome and induces placental inflammation, resulting in the incidence of absorption.

Palmitic Acid and β-Hydroxybutyrate Induce Inflammatory Responses in Bovine Endometrial Cells by Activating Oxidative Stress-Mediated NF-κB Signaling

Ketosis is a nutritional metabolic disease in dairy cows, and researches indicated that ketonic cows always accompany reproductive problems. When ketosis occurs, the levels of non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHBA) in the blood increase significantly. Palmitic acid (PA) is a main component of saturated fatty acids composing NEFA. The aim of this study was to investigate whether high levels of PA and BHBA induce inflammatory responses and regulatory mechanisms in bovine endometrial cells (BEND). Using an enzyme-linked immunosorbent assay, quantitative real-time PCR, and western blotting, we evaluated oxidative stress, pro-inflammatory factors, and the nuclear factor (NF)-κB pathway in cultured BEND cells treated with different concentrations of PA, BHBA, pyrrolidinedithiocarbamate (PDTC, an NF-κB pathway inhibitor), and N-acetylcysteine (NAC, an antioxidant). The content of malondialdehyde was significantly higher, the content of glutathione was lower, and antioxidant activity-glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity-was lower in treated cells compared with control cells. PA- and BHBA-induced oxidative stress activated the NF-κB signaling pathway and upregulated the release of pro-inflammatory factors. Moreover, PA- and BHBA-induced activation of NF-κB-mediated inflammatory responses was inhibited by PDTC and NAC. High concentrations of PA and BHBA induce inflammatory responses in BEND cells by activating oxidative stress-mediated NF-κB signaling.

Effect of a high-fat diet on the rat bladder wall and bioactive action of Brazil nut oil

High-fat diet-induced obesity is associated with metabolic disorders. The Brazil nut has bioactive substances and has been used to control the damage caused by obesity in several organs. The work intended to show the damage caused by high-fat diet in the bladder wall and if the Brazil nut oil added to the diet could ameliorate or reverse this effect. Sixty-day-old rats were divided into two groups: C (control, n = 30) and HF (high-fat, n = 30) diets. At 90 days, 10 animals of each group were sacrificed. The others were divided into 4 groups: C and HF (animals that maintained their previous diet, n = 10 for each group) and C / Bno and HF / Bno (animals whose control or high-fat diet was supplemented by Brazil nut oil, n = 10 for each group). Sacrifice occurred at 120 days, and the bladders were removed and analyzed. Epithelial height was increased in the HF compared to the C group. In contrast, the C / Bno had a lower epithelial height compared to the others. The percentage of collagen between the detrusor muscle fibers was significantly greater in C / Bno, HF and HF / Bno than in control group. The HF had a larger muscle fiber diameter than the C group, while the C / Bno presented lower values than the HF and HF / Bno groups. HF diets induced bladder wall damage. These changes in the rat's bladder wall were partially reversed by the Bno.

Pro- and anti-inflammatory effects of sulforaphane on placental cytokine production

Placental inflammation increases the risk of adverse pregnancy outcomes and possibly neurodevelopmental disorders in the offspring. Previous research suggests it may be possible to modulate the placental immune response to bacteria to favor an anti-inflammatory phenotype with dietary factors. Sulforaphane (SFN) is a dietary supplement with known anti-inflammatory activities, however, its effects on placental cytokine production are unclear. Therefore, we evaluated the effects of SFN on biomarkers of inflammation and neurodevelopment under basal conditions and a setting of mild infection. Placental explant cultures were established and treated with up to 10 μM SFN in the presence and absence of 10⁷ CFU/ml heat-killed E. coli. Concentrations of IL-1β, TNF-α, IL-6, sgp130, HO-1 and BDNF in conditioned medium were quantified by immunoassay. SFN increased antioxidant HO-1 expression in the absence, but not the presence, of infection. SFN inhibited IL-1β and IL-10, but tended to promote, TNF-α production by bacteria-stimulated cultures. IL-6 and BDNF were inhibited by SFN irrespective of co-treatment with E.coli. A negative regulator of IL-6 signaling, sgp130, was increased by SFN under basal conditions, but not in E. coli-stimulated cultures. These results suggest that SFN has mixed effects on the placenta inhibiting both pro-inflammatory (IL-1β) and anti-inflammatory factors (IL-10) but promoting regulators of oxidative stress and inflammation (HO-1 and sgp130) in an infection-dependent manner.